Mineral oil compositions having stabilized low pour points



Patented May 4, 1954 MINERAL OIL COMPOSITIONS HAVING STABILIZED LOW POUR BODJTS Orland M. Reiff, Woodbury, N. .11., assignor to Socony-Vacuum Oil Company, Incorporated, a corporation of New York No Drawing. Application March 21, 1952, Serial No. 277,909

17 Claims. 1 This invention relates to lubricating oil compositions. More particularly, it is concerned with oil compositions having stabilized low pour points.

As is well known, the A. S. T. M. pour point of of a small amount of an acidic organic compound, particularly an organic acid. The invention, therefore, comprises the use, in combination, in oil to provide a stable low pour point 5 therein of (1) a minor amount of a metal ora waxy mineral lubricating oil may be substanganic detergent type pour point depressant and tially lowered by adding to the oil a small amount (2) a minor amount of an organic acid. of a certain type of chemical agent having waxmodifying properties. Such agents are known as The metal Organic pour depressant pour point depressants. Oils of low pour point The inventien co p and is applicable are, of course, highly desirable for use where low to any metal organic detergent salt having pour temperatures are encountered. Thus, automodepressant properties. Salts of this character bile engine oils designed for winter use are gena e describ in detail in previously issued D erally fortified with pour depressants in order to eIltS 0f e present inventel, Viz, 2,197,835 provide easier starting and better lubrication of and 2,263,4 5. es Salts y b b y the engine parts in cold engines. defined as oil-miscible metal organic compounds A major problem has been encountered, howhaving a wax-substituted aryl nucleus therein. ever, in the use of pour depressants, viz,, po r These include: Wax-aryl metal oxides, such as point reversion. This is the tendency of an oil, metal p eit metal Salts of Wa y acids, which has had its pour point lowered by the addich as eelboXylates and y fi metal tion of a pour depressant, to revert to a higher Sa ts o wa y yacids, Such as p ur point when Subjected to temperature cycL- Wax-phenol carboxylates and metal salts of waxas, for example, during winter storage. aryl sulfonic acids, such as wax benzene sul- Thus, an oil containing a pour depressant may fon t Oth r m 110waX- r 1 c mp un have an initial A. S. T. M. pour point of -20 51, such as those shown in previously issued Patent but during storage may be found to be solid t No. 2,197,835 and sulfurized metal salts of the temperatures much higher than the original pour aforesaid y Such as those disclosed in detail point. This tendenc for pour point r rsi in previously issued Patent No. 2,263,445 are also has been found to be particularly pronounced includedwhere the pour depressant is of the metal deter- 3:; In general, it pp t the metal 00118113311- ent type. This type of pour depressant coment of the wax-aryl-metallo compound may be prises certain metal salts of organic acids which y metal Metals Which p o p c y are available commercially for use in lubricating useful ergent D depressants in O O oils, and which function as detergents as well as ever, belong the Silver, p aluminum, pour depressants. The two-fold action of these iron, alkali and alkaline earth analytical up salts is, of course, highly advantageous. Unespecially the alkaline earth D- The Salts fortunately, however, the problem of pour point f b m r r i l rly pr rr A n nreversion which is associated with their use, l ti x pl f u h mp und the f lgreatly discounts their value. 1 lowing may be mentioned:

It is the object of this invention to provide a 40 Barium waxmheml carboxylate ractical means of counteracting the pour rever- Calcium wax phenol carboxylate sion tendency in oil compositions containing these Aluminum waxlphenol carboxylate detergent salts as pour depressants, so that the sulfurized barium wax-phenol carboxylate pour points of such compositions are rendered Barium wax benzene sulf nate Substantially Stable Zinc wax-benzene sulfonate In accordance with the present invention, we Barium a -naphtha,1gne sulfonate have now found that the pour point of a lubricat- Calcium w h t ing oil which has been lowered by the addition Barium wax-phenate thereto of a detergent salt type pour point de- Lead wax-phenate pressant may be stabilized by addition to the oil 59 Sodium phenate of wax-phenol disulfide The acidic compound The acidic organic compounds capable of stabilizing the low pour point of an oil containing a pour depressant salt of the above described type include the following: Monoand poly-carboxylic acids of the aliphatic, aromatic and heterocyclic series. The aliphatic acid may be saturated or unsaturated and may have a molecular weight as low as formic acid or as high as montanicacid. Suitable saturated monobasic acids are, for example, formic, acetic, butyric, capric, palmitic, stearic and montanic acids. Unsaturated monobasic acids are acrylic acid, oleic acid and the like. Suitable saturated aliphatic polybasic acids includesuccini'c, adipic, and sebacic acids, while unsaturated polybasic acids include acids such as iumaric and maleic acids.

The aromatic monocarboxylic acid may be, for example, benzoic or naphthoic .acid while the polybasic acid may be an acid such as p'hthalic or terephthalic acid. Proper oil solubility of the aromatic acid can be assured by having one or more alkyl substituents, such as a butyl group, in the aromatic ring.

The 'heterocyclic carboxylic include, for example, furoic, alk-yla'ted iuroic and nicotinic acids.

Other types of acids which are suitable for use in the invention include non-benaenoid cyclic monoand polycarboxylic-acids, such as abietic and camphoric acids; alkane sulfonic acids, such as methane and ethane sulfonic acids; alkaryl sulfonic :acids, such as amyl phenyl sulfonic acid and wax .phenyl sulfonic acid; -.organic :acids of suliurgsuchas thiolacetic acid; :mercaptans, such as dodecyl mercaptan; alky'l hydrogen :phosphites and phosphates, such :as didecyl hydrogen phosphite; :alkaryl acid p'hosphites and phosphates, such as diamylphenyl .acid Lp'hosphite and :phosphate; alkane phosphinic and :phosphonic acids, such as dimethyl phosphinic, methyl-phosphcn'ic and dodecane phosphonic acids. The acids of the invention or'maynotacontain'other substituent groups, such as halogen, hydroxyl, amino, thio, keto, cyano, azo, nitro,eitc.

Although as aforestated, the principle of the invention is applicable to'metal organic detergent salt pour depressants in general, it will be illus- :trated herein by means of the sulfurized barium salt of wax-phenol 'carboxylate which is typical of the detergent-type pourdepressantzsalts contemplated herein.

Preparation of sulfurized barium wax-phenol carboxylaie (a) PREPARATION OF VVAX-ALKYLATED TPH'ENGL A paraiiin wax melting at approximately 1-20 F. and predominantly comprised of hydrocarbons having at "least 20 and an average :of about 24 carbon atoms in their molecules, is melted and heated to about 200 after which chlorine -is added until the desired weight (about 14 per cent) incorporated in the wax. A 'sufficient quantity of this chlorinated wax to provide 3 atomic proportions of chlorine is then heated to a temperature varying .i-rom just above its melting point to not over 150 One mol of phenol (ceHsOH) is then mixed with the chlorowax. The mixture is then heated to about 150 F. and a quantity of anhydrous aluminum chloride, cor responding to about 3 per cent of the weight of the chlorowax in the .mixture, is slowly added with active stirring. The rate of addition of the 250"13300350 F.1at a rate of approximately one degree per minute, the Whole heating operation occupying approximately two hours from the time of adding the aluminum chloride. If the emission -of H01 .gas has not ceased when the final temperature is reached, the mixture may be held at 350 F. fora short time to allow completion of the reaction. However, to avoid 1305 sib'le cracking of the wax, the mixtme should not be heated appreciably above 350 nor should at be held at that temperature for any extended length of time.

,It is important that all unreacted, or non-- alkylated, phenol remaining in the reaction mixture, well .asaluminum chloride, be removed. This can 'be conveniently effected by washing thep'roduct several'times'with amixture of water and an alcohol, such as butanol, preferably at elevated temperature, say 175 F. The product may then be treated with steam. This latter step will insure complete removal of the unrcacted material and 'also dry the product.

It will be understood that .a wax-substituted phenol prepared according to the above pro- 'cedure, .in which a quantity of chlorowax containing three atomic proportions of chlorine and. having a chlorine content of 14 per cent is reacted With one mol "of phenol, is designated as wax-phenol "(B-14). Similarly, wax-phenol (3-10) and wax-phenol may also be prepared by the reaction of sufiicient amounts of chlorinated wax, containing 10 per cent by weight of chlorine, to provide 3 atomic prcpcrtions and 1 atomic proportion of chlorine per mol of phenol, respectively, in the reaction are useful in the .invention. In general, an amount of chlorowax, containing from about 10 to 18 per cent by weight of chlorine may be in thereac'tionto supply between 1 and 4 atomic proportions of .chlorineper mol of phenol used. (in PREPARATION on THE SULFURIZED minim SALT OF WAX-Pl-IENOL CARBOXYLIC ACID (v.44

Barium oxide is reacted with methanol at room temperature to .form a solution-of barium math-- ylate. The reaction mixture is then filtered to obtain the pure solution which may contain amount of barium methylate equivalent to 16 per cent barium by weight.

One hundred grams of wax phenol, prepared as indicated in (-a), .is dissolved in of mineral oil (S. U. V. 100 sec. at 100 F.) and heated with stirring to 167 F. 'An amount of the barium methylate solution equivalent to 8.78 grams barium is then added while allowing the methanol .to distil. .After stirring for 15 minutes at 167.F., the temperature is gradually increased to 3.83 F. and CO2 is introduced over a el-hciu' reaction period at 383 to 395 F. The batch then cooled to 266 'F. preparatory to the introduction of elementary sulfur (3.88 grams) which is sprinkled in and the batch stirred for 15 min utesat 266 to 285 F. to insure complete solution of the sulfur. The whole is then cooled to 167 F,

Additional barium methylate, equivalent to 20.2 grams barium, is then added with the simultaneous distillation of methanol. After reacting the mixture 15 minutes, the temperature is gradually raised to 266 F., followed by filtration of the product through filtering clay. The filtrate is then analyzed for barium and diluted with additional mineral oil to give the finished product of 6 per cent barium content.

Pour point stability The ability of the acidic organic compounds herein contemplated in stabilizing the pour points of oils containing a pour depressant or the metal detergent type is demonstrated by the test results shown in Table I. In these tests oil blends of the sulfurized barium salt of waxphenol carboxylic acid (3-14) both with and without an added acidic compound were prepared and subjected to laboratory temperature cycling tests. The base oil used in all these tests was a mid-continent, solvent-refined oil having a kinematic viscosity of 8.39 centistokes at 210 F. and an A. S. T. M. pour point of +25 F. This oil was blended with 1 per cent by weight of a commercial additive consisting of 1 part of the sulfurized barium salt of wax-phenol carboxylic acid (3-14), prepared as described hereinabove, and 1 part of a reaction product of alpha-pinene with phosphorus pentasulfide (antioxidant). This blend had an A. S. T. M. pour point of -25 F. In the table, this oil blend is designated as Blend A. The other blends tested (containing the acidic organic compounds) were prepared by simply adding a small amount of the particular acidic organic compound to Blend A.

The test procedure involved the following steps:

1. Fifty-gram samples of the oil blends in standard, tall-form, four-ounce bottles were preheated to 115 F. and then allowed to cool to room temperature.

2. The samples were then cooled to -20 F. over a 22-hour period and maintained at this temperature for 24 hours.

3. The samples were allowed to warm to +50 F. over a 44-hour period and kept at this temperature for about 4 hours.

a. The samples were finally cooled to 20 F. over a 54-hour period. They were observed for fluidity at five-degree intervals beginning with +20 F. during the final cooling stage. In examining the sample for fluidity, it was first tilted slightly. If no flow was observed, the bottle was tilted to a horizontal position and held for five seconds. The sample was reported as being solid if no flow Was observed after this time. The stable pour point is reported as five degrees above the observed solid point.

Certain of the stable pour points shown in the table are reported as 15 F. which means that these blends were fluid at -15 F. which was the lowest temperature obtained in the final cooling stage of that particular test. Where a final temperature of -20 F. was attained, those blends which still flowed are reported as having stable pour points of -20 F.

It will be seen from the table that the stable pour point obtained for Blend A was +15 Ft, which amounts to a reversion of i degrees (from 25 F.), whereas in each of the other blends tested the acidic compound inhibited the reversion of the pour point, the greatest reversion being only degrees where 0.1 per cent by weight of the acidic compound was used; and, in certain instances where even smaller amounts of a, the acidic compound was used, reversion was substantially completely inhibited.

TABLE Compound Added To Blend A with; :55? cent 0 F None +15 Acetic Acid j 8 it? Stcaric Acid It? Abietic Acid j 3 Ii? Furoic Acid j Sebaeic Acid 3 Diglycolic Acid Maleic Anhydridc Phthalic Anhydride I}? Didodecyl Malonic Acid fig i2 Mixed Wethaneand Ethanesulfonic Acids. I}; Salicylic Acid j Anthranilic Acid H :1; Didecyl Hydrogen Phosphite i ;23 2 Dodccane Phosphonic Acid :28 Diarnyl Phcnyl Acid Phosphate 3? Magnesium Stearate The amount of the detergent-type pour depressant salt used in the oil is that suificient to substantially lower the pour point of the oil, i. e., from about 0.05% to about 5%, usually about 1.0% by weight. On the other hand, the amount of the acidic organic compound required to stabilize the pour point of the oil will be a minor amount, i. e., from about 0.01% up to about 1%, by weight, although usually from 0.01% to 0.10% is sufiioient. In blending certain of the less oilsoluble compounds, it is desirable to first prepare a concentrated solution in an alcohol, such as n-butanol, and then blend the desired concentration in the oil.

The pour stabilizing acidic compounds of the invention may be added to oils containing other improving agents along with the detergent-type pour depressant, such as antioxidants, extreme pressure agents, rust inhibitors, etc.

Concentrated oil blends of the stabilized additives of the invention may be prepared and marketed, such concentrates of the additives providing a readily soluble form of the additive combination for addition to further quantities of oil to improve the pour point characteristics thereof.

Although the invention has been illustrated herein by certain specific examples, it is not intended that the scope thereof be limited thereby in any way, but only as indicated by the appended claims in which it is intended to claim all novelty inherent therein as well as all modifications coming within the scope and spirit of the invention.

What is claimed is:

1. A lubricating oil composition having a stabilized low pour point comprising a major proportion of a waxy mineral lubricating oil, a minor proportion, suflicient to lower the pour point of said oil, of a metal salt of an organic acid having a wax-substituted aryl nucleus therein and a minor amount, sufiicient to stabilize the lowered pour point of said oil, of an organic acid.

2. A lubricating oil composition having a sta- 7. bilized low pour gpoint (comprising a major proportion of a waxyi-mineral lubricati-ng oil, a minor proportion, sufiicient .to lower the pour point of said oil, of a metal salt of an organic acid having a wax-substituted aryl nucleus therein and a minor amount, suflicient to stabilize the lowered pour point of said oil, of a carboxylic acid.

3. A lubricating oil composition having a stabilized low pour point comprising a major proportion of a waxy mineral lubricating oil, a minor proportion, sufilcient to lower the pour point of said oil, of a metal salt of an organic acid having a wax-substituted aryl nucleus therein and a minor amount, sufiicient to stabilize the lowered pour point of said oil, of a sulfonic acid.

4. A lubricating oil composition having a stabilized .low pour point comprising a major proportion of a waxy mineral lubricating oil, a minor proportion, su'flicient to lower the pour point or said oil, of a metal salt of an organic acid having a Wax-substituted aryl nucleus therein and a minor amount, sufficient to stabilize the lowered pour point of said oil, of an organic phosphoruscontaining acid.

5. A lubricating oil composition having a stabilized low pour point comprising a major proportion of a waxy mineral lubricating oil, a minor proportion, suflicient to lower the pour point of said oil, of a metal salt of a wax-substituted phenol carboxylic acid and a minor amount, sufficient to stabilize the lowered pour point of oil, of a carboxylic acid.

6. A lubricating :oil composition having a stabilized low pour point comprising a major proportion of a waxy mineral lubricating oil, a minor proportion, suflicient to lower the pour point of said oil, of a metal salt of a wax-substituted phenol and 'amin'orarnpunt, suii'icient to stabilize the lowered pour point of said o'il, 0f a carboxylic acid.

'7. A. lubricating oil composition having a stabilized low pour point comprising a major proportion of a waxy mineral lubricating oil, a minor proportion, sufficient to lower the pour point of said oil, of a metal salt of a wax-substituted aryl sulfonic acid and a minor amount, sufiicient to stabilize .the lowered pour point of said oil, of a carboxylic acid.

8. A lubricating oil composition having a sta- .-i]ized low pour point comprising a major proportion of a waxy mineral lubricating oil, a minor proportion, sufiicient to lower the pour point of said oil, of a metal salt of a wax-substituted phenol carboxylic acid and a minor amount, sufficient to stabilize the lowered .pour point of oil, of a sulfonic acid.

9. A lubricating oil composition having a stah' ized low pour point comprising a major proportion of a waxy mineral lubricating oil, a minor 11' wortion, sufiicient to lower the pour point of oil, of a metal salt 'of a wax-substituted phenol and a minor amount, sufiicient to stabilize the lowered pour point of said oil, of a sulfonic acid.

10. A lubricating oil composition having a staproportion, suflicient to lower the pour point of said oil, of :a metal salt of .a wax-substituted aryl sulfonic acid and a minor amount, sufiicient to stabilize the lowered pour point of said oil, of

sulionic acid.

1.1. A lubricating oil composition having a stabilized low pour point comprising a major proportion of a waxy mineral lubricating oil, a minor proportion, sufiioient to lower the pour point of said oil, of a metal salt of a wax-substituted phenol 'carboxylic acid and a minor amount, sufficient to stabilize the lowered pour point of said oil, of an organic phosphorus-containing acid.

12. Alubrica'tin-goi1-composition having a stabi-lized low pour point comprising a major proportion-of a waxy mineral lubricating oil, a minor proportion, sufiicient to lower the pour point of said oil, of a metal salt of a wax-substituted phenol and a minor amount, sufficient to stabilize the lowered pour point of said oil, of an organic phosphoruscontaining acid.

'13. A lubricating =oil composition having a stabilized low pour point comprising a major proportion of a waxy mineral lubricating-011, 2. minor proportion, .sufficient to lower the pour point of said .oil, of 1a sulfurized barium salt of a waxsubstituted phenol carboxylic acid and a minor amount, su'fiicient to stabilize the lowered pour point of said oil, of maleic:acid.

A lubricating oil composition having a stabilized low pour point comprising a major proportion'of a waxy mineral lubricating oil, a minor proportion, 'sumcient to lower the pour point of said 011, of a su'lfurized barium salt of a waxsucstitutcd phenol 'carboxylic acid and a minor amount, sufficient to stabilize the lowered pour point of said oil, of stearic acid.

15. A lubricating oil composition having a .stabilized low pour point-comprising a maj or :propor tion of a waxy mineral lubricating oil, a minor proportion, sufficient to lower the pour point of said oil, of a sulfurized barium salt of a wax-sub stituted phenol carboxylic :acid and a minor amount, sufficient to stabilize the lowered pour point 10f said oil, of salicycl-ic acid.

1-6. .A lubricating oil composition having a stabilized low pour point comprising a major proportion of a waxy mineral -lubricating oil,'a minor proportion, .saiiicient 'to lower the pour point of said oil, of a sulfurized barium salt of a waxsubst-ituted phenol carboxylic acid and a minor amount, sumci'ent to stabilize the lowered pour point of said oil, of dodecane phosphonic acid.

17.. A lubricating oil composition having a stabilized low pour point comprising a major proportion of a waxy mineral lubricating oil, a minor proportion, sufficient to lower the pour point of said oil, of barium Wax phenate and a minor amount, suflicien-t to stabilize the lowered pour point of said oil,.of :maleic acid.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,163,622 Neeley et'al June 27, 1939 2,197,835 'Reifif Apr. 23, 1940 

1. A LUBRICATING OIL COMPOSITION HAVING A STABILIZED LOW POUR POINT COMPRISING A MAJOR PROPORTION OF A WAXY MENIRAL LUBRICATING OIL, A MINOR PROPORTION, SUFFICIENT TO LOWER THE POUR POINT OF SAID OIL, OF A METAL SALT OF AN ORGANIC ACID HAVING A WAX-SUBSTITUTED ARYL NUCLEUS THERIN AND A MINOR AMOUNT, SUFFICIENT TO STABILIZE THE LOWERED POUR POINT OF SAID OIL, OF AN ORGANIC ACID. 